表皮生长因子受体／丝氨酸／苏氨酸蛋白激酶途径在三苯氧胺耐药人乳腺癌细胞株MCF-7形成中的作用

Role of epidermal growth factor receptor/protein kinase B signaling pathway in the generation of tamoxifen resistant MCF-7 breast cancer ceils

目的观察表皮生长因子受体（EGFR）／丝氨酸／苏氨酸蛋白激酶（AKT）途径在三苯氧胺（TAM）耐药人乳腺癌细胞株MCF-7形成过程的变化，及抑制该途径对肿瘤细胞周期的影响。方法用1×10^-7nmol/L的三苯氧胺诱导、建立三苯氧胺耐药细胞（TAM—R）细胞株，以荧光定量逆转录聚合酶链反应（flqRT—PCR）、Westernblot法、流式细胞术检测McF_7与TAM．R细胞中EGFRmRNA、P—AKT蛋白的表达及TAM—R细胞给予EGFR及AKT抑制剂后对细胞周期的影响。结果TAM—R细胞中EGFRmRNA和p-AKT蛋白的表达较MCF-7显著提高（P〈0．05）；给予ZD1839和SH-6阻断EGFR／AKT信号通路后，p-AKT表达受到抑制（P〈0．05），TAM—R细胞的G0—G1期比例提高，其中20μmoL／LZD1839组高达88％，细胞增殖指数下降（P〈0．05）。结论EGFR／AKT信号通路在MCF-7细胞对TAM耐药的形成中提供了非雌激素途径的生长信号。

Objective To investigate th-e change of epidermal growth factor receptor/protein kinase B （EGFR/AKT） signaling pathway in the generation of tamoxifen （TAM） resistant MCF-7 breast cancer cel^s and the impact on the tumor cell cycle by suppressing EGFR/AKT signaling pathway. Methods The TAM-R was derived from the wild type MCF-7 breast cancer cells continuously exposed to 1×10^-7 nmol/L d-hydroxy tamoxifen for 6 months. EGFR mRNA and p-AKT were detected by using fluorescent quantitation reverse transcription-polymerase chain reaction （fqRT-PCR） and Western blotting, respectively. Cell cycle was tested by flow cytometry. Results The expression levels of EGFR mRNA and p-AKT protein in TAM-R cells were higher （P 〈 0. 05） than those in MCF-7 cells. Inhibitors, ZD1839 and SH-6, suppressed the expression of p-AKT and the proliferation of TAM-R cells significantly. Conclusion The activation of EGFR/AKT signaling pathway may provide other growth signal, not estrogen, in tamoxifen resistant MCF-7 cells.